doc/go1.16: fix broken <code> tag
doc/go1.16: fix broken <code> tag

For #40700

Change-Id: I0083db494284d6142e1b8b981fca4ac30af2012a
Reviewed-on: https://go-review.googlesource.com/c/go/+/275312
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
Trust: Filippo Valsorda <4f40cda291c5f9634e1affd3db44947af61f705c@golang.org>

golang/go,cloudflare/go,golang/go,golang/go,CAFxX/go,cloudflare/go,cloudflare/go,nawawi/go,nawawi/go,cloudflare/go,nawawi/go,golang/go,golang/go,nawawi/go,cloudflare/go,CAFxX/go,cloudflare/go,golang/go,cloudflare/go,golang/go,CAFxX/go,CAFxX/go,CAFxX/go,nawawi/go,CAFxX/go,CAFxX/go,CAFxX/go,golang/go,nawawi/go,nawawi/go,cloudflare/go,nawawi/go